Are you afraid of living your life without electricity? Reading the following helps you know more about the electricity.

HIMALAYAL - SHANGHAI - CHINA

The night falls and the streets are brilliant. 

Most of us get used to living a life with electricity. However, have you ever experienced a power outage? Have you imagined what your day would be like without electricity. Actually, several massive power outages hit foreign countries. The power is suddenly off, leaving us in total darkness.  

To date, China has suffered no electrical blackout. China ranks among the best in the level of grid operation. What's the secret of secure power grid? Tang Yong, general engineer at China Electric Power Research Institute, tells us something more.  
 
   
 

Q: What are main challenges to electric power grid security we are facing now? 

A: The secure and stable operation of electric power system is related to social stability and economic development, which receives high attention from governments and electric companies. 

At present, as large quantities of equipment, including new resources power generation, DC power transmission and electric device, are increasingly used, an electric power system is becoming larger in scale and more complicated, posing a great challenge to secure and stable operation of electric power system.  

Besides, large-scale grid-connection of renewable electric resources provides green energies meanwhile it presents many challenges to secure and economic operation of electric power system. For instance, the wind power has become the second largest power source in North China, Northeast China and Northwest China while the wind power output in part of provinces of Northwest China even accounts for above 50%. The dynamic characteristic of intermittent new energy has become one of crucial factors, which have an influence on secure and stable operation of electric power system. 

Ushering in the era of Internet, the integration of technology and industry stimulates the innovation but represents a new challenge to power internet security. Ukraine suffered the first world massive power outage caused by cyber hacking at the end of 2015, which illustrates that the internet security has become a key part of power security.  

Q: Ensuring the security of massive power system is a complex issue, involving many aspects that include power grid structure, automatic control and operation mode etc. What are main challenges to the secure operation of electric power system. 

A: Companies are at the period of transition -- UHV grid“strong DC and weak AC”. Important changes are made to the characteristic of grid. All presents new requirements for secure operation of grid. In terms of operation, the AC and DC grid is closely connected with sending & receiving end coupling; interactive capacity between regions increases; the feature of power integration intensifies. 

For example, in the DC power transmission, “commutation” is a key link between DC and AC. Generally speaking, commutation failure would generate great impact. Therefore, the construction of UHV DC must be strengthened to bear the power impact from breakdowns such as DC commutation failure.  

In addition, the uncertainty of electricity side and the randomness caused by new resources connection and distributive energy development further intensify the difficulty of controlling and adjusting the electric power system.  

Q: The company is building the world’s largest AC and DC hybrid electric power system with highest voltage stage. What is essential to ensure secure and stable operation of electric power system? 

A: With regard to power system planning and operation, security is always a high priority. The strong and comprehensive security defense system must be built in order to prevent the power outage and make sure that the electric power system runs stably and securely.

Ensuring the security of massive power system is a complex issue, involving many aspects that include power grid structure, automatic control and operation mode etc. What are main challenges to the secure operation of electric power system. 

In general, a comprehensive security defense system of electric power system can be divided into two aspects: security system before power system disturbance (active security) and stability control system after power system disturbance (passive security).

Q: In terms of active security and passive security, how to build the comprehensive defense system to meet the requirements of power grid development in future? 

A: The electric power security system (active security) mainly includes “three defenses”, that is, strong grid, optimal automatic control system and secure operation mode.

First of all, a strong grid lays the foundations for secure electric power system. A strong grid must provide power reliably and consistently, regardless of human error, poor planning and extreme weather events. 

Secondly, a optimal automatic control system is essential to improve the level of secure operation. It is necessary to take full advantage of latest control theory and wide area information to address the problems of operational control during the period of “strong DC and weak AC” transition and optimize the automatic control system. More researches on the application of AC and DC wide area control technologies should be undertaken to improve the comprehensive control capacity and the level of secure and stable operation for the grid. 

At last, secure operation mode can guarantee that the electric power system operates securely. With the development of electric power system, the large-capacity DC feeds into the receiving-end system and the proportion of power-receiving power is increasing. Hence, we need to constantly optimize new operation technologies and modes to meet the new requirements of electric power system advancement. 

The stability control system of electric power system (passive security) also includes “ three defenses”-- rapidly eliminating broken components, taking stability and control measures and taking emergency measures when the system becomes unstable.